feat: M0 monorepo skeleton with services, clients, deploy and CI

- api/openapi.yaml: contract with /healthz, /readyz, /api/v1/server-info
- services/api (Go): api with oapi-codegen strict server, goose migrations,
  readiness checks for Postgres/Redis; storage-agent stub with internal token
- services/recommender (Python, uv): FastAPI health/readiness/internal status,
  `pipu-rec serve` and `pipu-rec analyze` entrypoints
- packages: generated api-client, core (server URL + server check),
  i18n (ru/en + dictionary check), design-tokens (CSS vars + TS from tokens.json)
- apps/web: Vite + React shell showing server status, language switch
- apps/mobile: Expo (SDK 53) Android app with server connect screen
- deploy: Dockerfiles, compose (prod + dev), nginx template, install/update scripts
- .gitea/workflows: ci.yml and tag-based release.yml (images, signed APK, release)
- scripts/version.mjs: version and Android versionCode from git tag
- tests/fixtures/music/generate.sh: synthetic test library via ffmpeg
- docs: versionCode formula, OpenAPI 3.0.3, dev instructions in README

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/mobile.md

@@ -83,7 +83,7 @@
 **Требования:**
 - В манифесте: `REQUEST_INSTALL_PACKAGES`, `FileProvider`.
 - Все релизы подписываются **одним и тем же ключом** (keystore в секретах CI) — иначе Android откажет в обновлении.
-- `versionCode` монотонно растёт: `major·10000 + minor·100 + patch` (см. [ci-cd.md](ci-cd.md)).
+- `versionCode` монотонно растёт: `major·1 000 000 + minor·10 000 + patch·100 + (99 | rc)` (см. [ci-cd.md](ci-cd.md#версионирование)).
 - Ассеты релиза: `pipu-music-<version>.apk`, `pipu-music-<version>.apk.sha256`.
 
 ## Безопасность